A Dutch version of the renowned German c't magazine published a short review of The Bat! Voyager. We don’t speak any Dutch, but it wasn’t hard to realize that the article’s title – “Vleermuis” – stands for “Bat”. And here’s a rough translation of the article’s subheading: “The Bat! Voyager is a mail client which offers more than most of the others”.
If your Dutch is better that ours, you can read the complete version of the review here